1. Field of the Invention
The present invention relates to an integrated structure of a mobile communication and wireless local area networks, and more particularly, to handling charging (billing) information when both a WLAN service and a mobile communication network service are used.
2. Description of the Related Art
Recently, various techniques for interworking (i.e., integrating or converging) a mobile communication network with a wireless local area network (WLAN) to allow mobile communication network services and WLAN services to be used together are being developed.
Mobile communication networks and wireless local area networks will be considered here for exemplary purposes. However, this is not meant to limit the applicability of the present invention teachings in any way.
FIG. 1 illustrates an example of how the services of a wireless local area network (WLAN) and of a mobile communication network can be provided together to various users.
As shown in FIG. 1, a WLAN uses IEEE 802.11 standard technology and HIPERLAN technology to support low-cost, high-speed wireless communications in “hot spot” regions, such as airports or schools, where there are many users. Also, a mobile communication network employs third generation technology, such as cdma2000 or WCDMA, to support high mobility wireless communications.
In the interworking network structure of FIG. 1, a user employing a single wireless communication device (e.g., user equipment (UE)), can access a low-cost WLAN in a hot spot region that supports WLAN wireless access services, while in other regions, the user can access a mobile communication network to receive wireless communication services. Here, the interworking network structures can be classified into two types according to the services requested by the user as follows.
The first type of interworking network structure is a configuration in which the authentication and charging (billing) for usage of the WLAN and the mobile communication network are combined and managed, and the WLAN and mobile communication network service provision are operated independently. Namely, the authentication and charging for the WLAN communication service are provided through the authentication server and the charging server of the mobile communication network.
The second interworking network structure is a configuration in which authentication and charging are combined and managed as in the first interworking network structure, while additional services exclusively provided from the mobile communication network is provided to the user via a WLAN wireless access service. Namely, in the second interworking network structure, while using WLAN wireless access services, additional services provided by the mobile communication network are also provided together therewith.
The related art and the present invention will be described with reference to the second type of interworking network structure shown in FIGS. 2 and 3, comprising a mobile communication network and a WLAN are connected, wherein a 3GPP home network 220 is used as the mobile communication network for exemplary purposes.
In FIG. 2, there is an AAA (Authentication, Authorization, Accounting) server 222, which is a network element of the 3GPP home network (mobile communication network) 220 responsible for handling communication usage authorization and charging information for wireless communication users. The HSS/HLR (Home Location Register/Home Subscriber System) 224, 226, connected with the AAA server 222, are network elements that manage information regarding the users registered with the mobile communication network. The OCS (Online Charging System) 228, connected to the AAA server 222, is a network element that manages in an on-line manner the communication service usage amount so that pre-paid users are provided with services that are limited to their pre-paid budget. The CGw/CCF (Charging Gateway/Charging Collection Function) 230, connected with the AAA server 222, is a network element that collects and manages charging information for users. The Packet Data Gateway (PDGW) 240 is a node to allow access from the WLAN 210 to the services provided by the mobile communication network 220.
In the interworking network of FIG. 2, user equipment (UE) 200 may request a service from the 3GPP home network 220 via a WLAN. Here, user data traffic is sent not only to the WLAN access network 210, but also to the packet data gateway 240 in the 3GPP home network 220. When WLAN communication services and services of the mobile communication network are both provided during a single session (i.e., in one call connection), charging (billing) for both services must be applied properly.
In the interworking network structure of FIG. 2, charging information for the communication service of a related art WLAN is generated at the WLAN access network 210 and sent to the CGw/CCF 230 via the AAA server 222.
Thereafter, the CGw/CCF 230 uses the charging information provided by the AAA 222 server to calculate the service usage charges of using the communication services of the WLAN and using the additional services of the mobile communication network.
FIG. 3 illustrates the second type of interworking network structure wherein the mobile communication network provides additional services. The structure of FIG. 3 is the same as that of FIG. 2, but with the addition of a mobile (communication) network additional service provision node 350 connected with the PDGW 340 and the CGw/CCF 330. Here, the mobile communication network additional service provision node supports the providing of additional services, such as Internet protocol (IP) multimedia service (IMS), multimedia message service (MMS), multicast and broadcast multimedia service (MBMS) or other multimedia services, by the mobile communication network.
In FIG. 3, similar to FIG. 2, user equipment (UE) 300 may request an additional service from the 3GPP home network 320 via a WLAN. Here, user data traffic is sent from the additional service provision node 350 of the 3GPP home network 320 to the UE 300 via the PDGW 340 and the WLAN access network 310. When additional services of the mobile communication network are provided via the WLAN access network during a single session (i.e., in one call connection), charging (billing) for usage of WLAN access network services and charging (billing) for usage of additional services of the mobile communication network must be applied properly.
In the interworking network structure of FIG. 3, charging information for the communication service of a related art WLAN is generated at the WLAN access network, 310 and sent to the CGw/CCF 330 via the AAA server 322. Meanwhile, the charging information for the additional service of the mobile communication network is generated at the additional service provision node 350 and sent to the CGw./CCF 330.
Thereafter, the CGw/CCF 330 uses the charging information provided by the AAA 322 server and the additional service provision node 350, respectively, to calculate the service usage charges of using the wireless access services of the WLAN and using the additional services of the mobile communication network.
For interworking networks, efforts are being made to allow the charging functions ordinarily provided by the WLAN, to be handled by the mobile communication network. Related art service charging and billing methods consider two types of charging functions; pre-payment charging and post-payment charging.
FIG. 4A illustrates one example of service authorization and charging methods according to the related art. Referring to FIG. 4A, when a user (customer or subscriber) requests setup (establishment) of a call for communication with the interworking network (step 1); the AAA server requests from the HSS/HLR, user information that is necessary for authentication (step 2); the HSS/HLR sends the requested user information to the AAA server (step 3); and the AAA server authenticates the user according to the user information.
Then, for pre-payment users, the AAA server inquires the OCS regarding the remaining balance for the user to ensure that the user does not exceed the pre-paid limit of his service usage (step 5a).
For all users, the AAA server informs the CGw/CCF of the service usage amount and then after a certain period of time, the entire service use amount is confirmed and the charges associated with that use is charged and billed to the user (step 5b).
FIG. 5A illustrates another example of service authorization and charging methods according to the related art. FIG. 5A shows a process of collecting charging information for information related to charging (communication service usage amount) according to service usage after the setup and authentication steps are successfully completed for a user wishing to receive wireless access services from the WLAN and services from the mobile communication network.
When a user requests to use the interworking network (step 1), the AAA server obtains authentication information and charging method information for the user from the HSS.HLR, and performs authorization. Once authorization is successful, the AM server informs the WLAN about the approved authorization and the pre-set transmitting period for sending the charging information (steps 2 and 3). The WLAN access network then allows communication to begin and the communication between the user and the network commences (step 4).
Once communication begins, the WLAN periodically sends the service usage amount to the AAA server (step 5). Then, the AAA server, according to the charging method for the user, cooperates with the OCS to check whether the service usage amount is within the pre-paid amount for pre-payment users (step 6). If the service usage amount exceeds the pre-paid amount, the user is informed via the WLAN that communications shall end. For all users, the AAA server sends the service usage amount information from the WLAN to the CGw/CCF (step 7).
FIG. 6A is a flow diagram showing the steps in providing an additional service from the mobile communication network via the communication service of the WLAN.
In steps 1 and 2, WLAN validation and authentication of the communication service for the user takes place, and in steps 3 and 4, the authentication for the additional service of the mobile communication network occurs. Here, the use authentication of the communication service at the WLAN is performed at the AAA server, while the use authentication of the additional service of the mobile communication network is performed by the additional service provision node in the 3GPP home network.
Thereafter, when actual communication begins and both the WLAN wireless access service and the additional service of the mobile communication network are provided during a single session (one call connection), as shown in steps 5a and 5b, the CGw/CCF of the mobile communication network periodically collects the charging information of the WLAN and the mobile communication network and calculates the use charges for the WLAN wireless access service and the additional service of the mobile communication network.
In the CGw/CCF, the use charges are calculated on the basis of the amount of communication service and amount of additional service during a user's session (one call connection). The charging information are collected and calculated by using the charging information for the communication service of the WLAN and the charging information for the additional service of the mobile communication network (also based on the user's session), that are recorded and used as identifiers (or standard values) for calculation.
The CGw/CCF collects the charging information from the WLAN and the mobile communication network by using a session ID and a charging ID as identifiers for discriminating between the charging information per each user session for the WLAN and the mobile communication network. In the WLAN, the session ID is generated by an access point (AP) existing within the WLAN access network, and the charging ID is generated by the additional service provision node within the mobile communication network.
Here, the session ID provided by the WLAN can differ depending upon the protocol used in the WLAN and can have a length of, for example, less than 4 bytes, while the charging ID provided by the mobile communication network can have a length of, for example, 4 bytes or more.
As described above, regarding the charging information in an interworking network of a wireless communication system, the charging information of the WLAN wireless access service and that of the mobile communication network additional service are independently collected. Here, the charging information for the WLAN wireless access service employing a session ID as an identifier (standard value) and is sent to the CGw/CCF via the AAA server in the WLAN access network, while the charging information for the mobile communication network additional service employing the charging ID is sent from the additional service provision node directly to the CGw/CCF.
However, in the second type of interworking network structure, when the user is provided with additional services from the mobile communication network via the WLAN wireless access service, the charging information for the WLAN wireless access service and for the mobile communication network additional service, respectively, are independently collected. Also, respectively different identifiers are uses to distinguish the charging information of the WLAN and that of the mobile communication network according to each session.
Accordingly, even if the charging information generated for a single session from the WLAN and the mobile communication network are collected by the CGw/CCF, because the CGw/CCF is not aware of any relationship between the session ID and the charging ID, the CGw/CCF cannot determine that the charging information from the AAA server and the additional service provision node, respectively, are for the same session. Namely, the CGw/CCF cannot determine that the two types of charging information were generated for a single connection between the user and the two networks. This type of problem exists not only for IMS services, but also for 3GPP services such as MMS and MBMS.
As such, when supporting an additional service provided by the mobile communication network via the WLAN wireless access service, the network provider has difficulties in accurately collecting and managing charging information for users of the interworking network. In particular, the network provider cannot calculate accurate charges per each session, and thus cannot provide accurate billing per session to interworking network users.